1)You are the director of a top secret government espionage agency. Every month you securely transmit a new set of one time pad values to each of the spies you have placed in various countries. Each of these values is used to encrypt a single message back to headquarters and then destroyed. You realize that last month the same pad was accidentally sent to every spy. Does this ruin the security of your system? Under what circumstances? What if one spy received the same pad two months in a row instead? Explain your answers. [Note: “pad” is the “key”]
2)A 3 bit long message was encrypted using one-time pad to yield a cipher-text “110” Assuming the message space consists of all 3 bit long messages, what is the probability that the corresponding plain-text was “101”? Explain your answer.
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1 response so far ↓
1 Oin L // Sep 16, 2008
i feel like im back in college…
some hints
1) pad 2 times in row time to get new spies as these are now compromised.
2) bits ie 1 or 0 so make a matrix
111 101 100
001 010 011
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